Table 1. Basic characteristics of the included studies.
| First author | Year | Country | Participants | Methods | Cutoff value | TP | FP | FN | TN | QUADAS score |
|---|---|---|---|---|---|---|---|---|---|---|
| George Sgourakis | 2014 | Germany | 71 | ELISA | 8.83 pg/ml | 48 | 3 | 8 | 12 | 12 |
| Zhang Pengjun | 2013 | China | 218 | Magnetic Beads | 44.26 pg/ml | 129 | 2 | 20 | 67 | 12 |
| Stefanie Bunger | 2012 | Germany | 133 | biochips | 39.5 pg/ml | 18 | 5 | 63 | 47 | 10 |
| ZHI YAN | 2012 | China | 96 | PCR | NA | 45 | 11 | 3 | 37 | 10 |
| J. Kaminska | 2005 | Poland | 207 | ELISA | 17.71 pg/ml | 106 | 1 | 51 | 49 | 11 |
NA, not available; ELISA, enzyme linked immunosorbent assay; PCR, polymerase chain reaction; TP, true positive; FP, false positive; FN, false negative; TN, true negative; QUADAS, Quality Assessment of Diagnostic Accuracy Studies.